121618557 has 8 divisors (see below), whose sum is σ = 180175680. Its totient is φ = 81079020.

The previous prime is 121618543. The next prime is 121618559. The reversal of 121618557 is 755816121.

It is not a de Polignac number, because 121618557 - 2⁷ = 121618429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121618559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2252169 + ... + 2252222.

It is an arithmetic number, because the mean of its divisors is an integer number (22521960).

Almost surely, 2^121618557 is an apocalyptic number.

It is an amenable number.

121618557 is a deficient number, since it is larger than the sum of its proper divisors (58557123).

121618557 is an equidigital number, since it uses as much as digits as its factorization.

121618557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4504400 (or 4504394 counting only the distinct ones).

The product of its digits is 16800, while the sum is 36.

The square root of 121618557 is about 11028.0803859965. The cubic root of 121618557 is about 495.4501323258.

The spelling of 121618557 in words is "one hundred twenty-one million, six hundred eighteen thousand, five hundred fifty-seven".